Bovine eimeriosis or coccidiosis is an intestinal disease caused by Eimeria spp. which is related to gastrointestinal disorders and, in some cases, death. The current work aimed to identify and provide detailed morphological characteristic features of the different Eimeria spp. parasites of crossbred cows of a subtropical organic dairy farm in Brazil, offering tools for the diagnosis of bovine eimeriosis. Eimeria auburnensis, Eimeria bovis, Eimeria bukidnonensis, Eimeria canadensis, Eimeria cylindrica, Eimeria ildefonsoi, and Eimeria zuernii were identified. The application of line regressions and ANOVA provided a means for the identification of these species. Finally, the current work proposes a dichotomous key to assist in the morphologic identification of bovine Eimeria spp. oocysts.

A description of the coccidium Isospora hemidactyli from the house gecko Hemidactylus mabouia, a very common at dwellings in Rio de Janeiro Metropolitan Region, was made in this study. Histograms and linear regression were made for this species and determined the homogeneity of these oocysts despite of large range. Besides it, polysporocystid oocysts also were recovered from feces of the H. mabouia house gecko and they were similar to those described previously as the genus Adelina. This species should be parasitizing an invertebrate ingested by house gecko, and for that reason, is a pseudoparasite. Oocysts of I. hemidactyli were subspherical to ellipsoidal, 24.4 × 22.3μm, with single-layered wall and one polar granule. Sporocysts were subspherical to ellipsoidal, 11.8 × 9.8μm with Stieda and substieda bodies, residuum and sporozoites with refractile body. Oocysts of the pseudoparasite Adelina sp. were ellipsoidal, 36.3 × 30.9μm, with bi-layered wall and without micropyle, residuum and polar granule. Eight to 15 sporocysts were presents and were subspherical to broadly ellipsoidal, 12.4 × 11.2μm. Stieda and substieda bodies were absent. Sporozoites present refractile bodies at both ends.

A new coccidian species (Protozoa: Apicomplexa: Eimeriidae) are reported from the white-necked thrush Turdus albicollis Vieillot, 1818, a very common species in South America. Isospora massardi sp. nov. oocysts are subspherical, 18.6 × 17.7 μm, with smooth, bilayered wall, ~0.9 μm. Micropyle, oocyst residuum are absent, but two polar granules are frequently present. Sporocysts are ovoidal, 14.8 × 9.3 μm. Stieda body is knob-like to rounded and substieda body is rounded. Sporocyst residuum is composed of scattered spherules of different sizes. Sporozoites are vermiform with posterior and anterior refractile bodies and a nucleus. This is the sixth description of an isosporoid coccidium infecting a New World turdid bird.

Non-human primates are our closest relatives and represent an interesting model for comparative parasitological studies. However, research on this topic particularly in relation to intestinal parasites has been fragmentary and limited mainly to animals held in captivity. Thus, our knowledge of host-parasite relationships in this species-rich group of mammals could be considered rudimentary. The current study combined morphological, ultrastructural, and molecular analyses to characterize isolates of intestinal tetratrichomonads recovered from the feces of three species of South American, non-human primates. Fecal samples were collected from 16 animals, representing 12 distinct species. Parabasalid-like organisms were evident in five samples (31%) of feces: two from Alouatta sara, two from Callithrix penicillata, and one from Sapajus apella. The five samples presented morphologies consistent with the description of Tetratrichomonas sp., with four anterior flagella of unequal length, a well-developed undulating membrane, and a long recurrent flagellum. Sequencing of the ITS1-5.8S rRNA-ITS2 region demonstrated that the isolates from A. sara, and C. penicillata were closely related and highly similar to isolates of Tetratrichomonas brumpti, recovered previously from tortoises (Geochelone sp.). The flagellate recovered from S. apella demonstrated a similar morphology to those of the other isolates, however, sequence analysis showed it to be identical to an isolate of Tetratrichomonas sp. recovered from white-lipped peccaries (Tayassu pecari). The findings of this study extend and enhance our knowledge of parasitism of non-human primates by members of the genus Tetratrichomonas and indicate that the host range of these parasites is broader than previously believed.

Isospora vanriperorum from the green-winged saltator (Saltator similis) is described in Southeastern Brazil. Oocysts are spherical to subspherical, 19.4-26 by 18.3-26 micro (23.1 by 22.4 micro), shape index 1.04 with a single layered wall, fine, smooth and yellowish. Micropyle and residuum are absents, but one elliptical polar granule is present. Sporocysts are ovoid, 14.5-20.2 by 8.1-12.5 micro (16.3 by 10.8 micro), shape index 1.53 with prominent Stieda body, barely discernible substieda body and residuum centered and granulated.

A new coccidian species (Protozoa: Apicomplexa: Isospora) parasitizing the white-shouldered fire-eye Pyriglena leucoptera (Vieillot, 1818) is described in the Parque Nacional do Itatiaia. This park is a protected area in southeastern Brazil with a high degree of vulnerability, representing a "conservation island" of biodiversity. Isospora parnaitatiaiensis n. sp. has oocysts that are ellipsoidal, 23.8 × 19.4 μm, with smooth, bilayered wall, ~1.1 μm thick. Micropyle and oocyst residuum are absent, but one or two polar granules are present. Sporocysts are ellipsoidal, 14.6 × 9.3 μm. The Stieda body is nipple- to knob-like and sub-Stieda body rounded to rectangular. Sporocyst residuum is present, usually as a cluster of numerous granules. Sporozoites are vermiform with two refractile bodies and a nucleus. This is the second isosporoid coccidian described from antbirds (Thamnophilidae).

A new coccidian species parasitizing white-necked thrushes Turdus albicollis Vieillot, 1818 is described from the Parque Nacional do Itatiaia, in Southeastern Brazil. Isospora machadoae sp. nov. has oocysts that are sub-spherical, 22.2 × 21.2 µm, with bilayered wall, ~1.3 μm thick. Outer layer is rough with micropyle and micropyle cap. Oocyst residuum is absent, but one or two polar granules are present. Sporocysts are ellipsoidal, 13.3 × 9.7 µm. The Stieda body is flattened to half-moon-shaped and substieda body rounded. Sporocyst residuum is present, composed of scattered spherules of different sizes. Sporozoites are vermiform with a refractile body and a nucleus. These parasitized thrushes had no apparent clinical signs of coccidiosis or high densities of oocysts in feces. This condition may be associated with a specific low pathogenicity of I. machadoae sp. nov. and/or with the conserved habitat of these birds, which ensures the ecological niches and thus the immunocompetence to wildlife.

The New World tyrant-flycatcher (Tyrannidae) Attila rufus (Vieillot, 1819) is commonly known as grey-hooded attila or 'capitão-de-saíra' in Brazil (Sick 1997; CBRO 2014). This species has a wide distribution and their population trends appear to be stable; therefore, it is least concern according to IUCN (2015) criteria.